database: Fix errorlint warnings.

database/cmd/dbtool/insecureimport.go

@@ -1,12 +1,13 @@
 // Copyright (c) 2015-2016 The btcsuite developers
-// Copyright (c) 2016-2019 The Decred developers
+// Copyright (c) 2016-2020 The Decred developers
 // Use of this source code is governed by an ISC
 // license that can be found in the LICENSE file.
 
 package main
 
 import (
 	"encoding/binary"
+	"errors"
 	"fmt"
 	"io"
 	"os"
@@ -70,7 +71,7 @@ func (bi *blockImporter) readBlock() ([]byte, error) {
 	var net uint32
 	err := binary.Read(bi.r, binary.LittleEndian, &net)
 	if err != nil {
-		if err != io.EOF {
+		if !errors.Is(err, io.EOF) {
 			return nil, err
 		}
 
@@ -376,8 +377,10 @@ func (cmd *importCmd) Execute(args []string) error {
 		resultsChan := importer.Import()
 		results := <-resultsChan
 		if results.err != nil {
-			dbErr, ok := results.err.(database.Error)
-			if !ok || ok && dbErr.ErrorCode != database.ErrDbNotOpen {
+			var dbErr database.Error
+			if !errors.As(results.err, &dbErr) ||
+				dbErr.ErrorCode != database.ErrDbNotOpen {
+
 				shutdownChannel <- results.err
 				return
 			}

database/cmd/dbtool/main.go

@@ -1,11 +1,12 @@
 // Copyright (c) 2015-2016 The btcsuite developers
-// Copyright (c) 2016-2019 The Decred developers
+// Copyright (c) 2016-2020 The Decred developers
 // Use of this source code is governed by an ISC
 // license that can be found in the LICENSE file.
 
 package main
 
 import (
+	"errors"
 	"os"
 	"path/filepath"
 	"runtime"
@@ -37,7 +38,8 @@ func loadBlockDB() (database.DB, error) {
 	if err != nil {
 		// Return the error if it's not because the database doesn't
 		// exist.
-		if dbErr, ok := err.(database.Error); !ok || dbErr.ErrorCode !=
+		var dbErr database.Error
+		if !errors.As(err, &dbErr) || dbErr.ErrorCode !=
 			database.ErrDbDoesNotExist {
 
 			return nil, err
@@ -94,7 +96,8 @@ func realMain() error {
 	// Parse command line and invoke the Execute function for the specified
 	// command.
 	if _, err := parser.Parse(); err != nil {
-		if e, ok := err.(*flags.Error); ok && e.Type == flags.ErrHelp {
+		var e *flags.Error
+		if errors.As(err, &e) && e.Type == flags.ErrHelp {
 			parser.WriteHelp(os.Stderr)
 		} else {
 			log.Error(err)

database/driver_test.go

@@ -1,11 +1,12 @@
 // Copyright (c) 2015-2016 The btcsuite developers
-// Copyright (c) 2016-2019 The Decred developers
+// Copyright (c) 2016-2020 The Decred developers
 // Use of this source code is governed by an ISC
 // license that can be found in the LICENSE file.
 
 package database_test
 
 import (
+	"errors"
 	"fmt"
 	"testing"
 
@@ -16,8 +17,8 @@ import (
 // checkDbError ensures the passed error is a database.Error with an error code
 // that matches the passed error code.
 func checkDbError(t *testing.T, testName string, gotErr error, wantErrCode database.ErrorCode) bool {
-	dbErr, ok := gotErr.(database.Error)
-	if !ok {
+	var dbErr database.Error
+	if !errors.As(gotErr, &dbErr) {
 		t.Errorf("%s: unexpected error type - got %T, want %T",
 			testName, gotErr, database.Error{})
 		return false
@@ -91,7 +92,7 @@ func TestCreateOpenFail(t *testing.T) {
 	// Ensure creating a database with the new type fails with the expected
 	// error.
 	_, err := database.Create(dbType)
-	if err != openError {
+	if !errors.Is(err, openError) {
 		t.Errorf("expected error not received - got: %v, want %v", err,
 			openError)
 		return
@@ -100,7 +101,7 @@ func TestCreateOpenFail(t *testing.T) {
 	// Ensure opening a database with the new type fails with the expected
 	// error.
 	_, err = database.Open(dbType)
-	if err != openError {
+	if !errors.Is(err, openError) {
 		t.Errorf("expected error not received - got: %v, want %v", err,
 			openError)
 		return

database/error.go

@@ -1,11 +1,14 @@
 // Copyright (c) 2015-2016 The btcsuite developers
-// Copyright (c) 2016 The Decred developers
+// Copyright (c) 2016-2020 The Decred developers
 // Use of this source code is governed by an ISC
 // license that can be found in the LICENSE file.
 
 package database
 
-import "fmt"
+import (
+	"errors"
+	"fmt"
+)
 
 // ErrorCode identifies a kind of error.
 type ErrorCode int
@@ -199,6 +202,6 @@ func makeError(c ErrorCode, desc string, err error) Error {
 
 // IsError returns whether err is an Error with a matching error code.
 func IsError(err error, code ErrorCode) bool {
-	e, ok := err.(Error)
-	return ok && e.ErrorCode == code
+	var e Error
+	return errors.As(err, &e) && e.ErrorCode == code
 }

database/ffldb/db.go

@@ -8,6 +8,7 @@ package ffldb
 import (
 	"bytes"
 	"encoding/binary"
+	"errors"
 	"fmt"
 	"os"
 	"path/filepath"
@@ -145,13 +146,13 @@ func convertErr(desc string, ldbErr error) database.Error {
 		code = database.ErrCorruption
 
 	// Database open/create errors.
-	case ldbErr == leveldb.ErrClosed:
+	case errors.Is(ldbErr, leveldb.ErrClosed):
 		code = database.ErrDbNotOpen
 
 	// Transaction errors.
-	case ldbErr == leveldb.ErrSnapshotReleased:
+	case errors.Is(ldbErr, leveldb.ErrSnapshotReleased):
 		code = database.ErrTxClosed
-	case ldbErr == leveldb.ErrIterReleased:
+	case errors.Is(ldbErr, leveldb.ErrIterReleased):
 		code = database.ErrTxClosed
 	}
 

database/ffldb/driver_test.go

@@ -183,20 +183,20 @@ func TestPersistence(t *testing.T) {
 
 		bucket1, err := metadataBucket.CreateBucket(bucket1Key)
 		if err != nil {
-			return fmt.Errorf("CreateBucket: unexpected error: %v",
+			return fmt.Errorf("CreateBucket: unexpected error: %w",
 				err)
 		}
 
 		for k, v := range storeValues {
 			err := bucket1.Put([]byte(k), []byte(v))
 			if err != nil {
-				return fmt.Errorf("Put: unexpected error: %v",
+				return fmt.Errorf("Put: unexpected error: %w",
 					err)
 			}
 		}
 
 		if err := tx.StoreBlock(genesisBlock); err != nil {
-			return fmt.Errorf("StoreBlock: unexpected error: %v",
+			return fmt.Errorf("StoreBlock: unexpected error: %w",
 				err)
 		}
 
@@ -241,7 +241,7 @@ func TestPersistence(t *testing.T) {
 		genesisBlockBytes, _ := genesisBlock.Bytes()
 		gotBytes, err := tx.FetchBlock(genesisHash)
 		if err != nil {
-			return fmt.Errorf("FetchBlock: unexpected error: %v",
+			return fmt.Errorf("FetchBlock: unexpected error: %w",
 				err)
 		}
 		if !reflect.DeepEqual(gotBytes, genesisBlockBytes) {

database/ffldb/interface_test.go

@@ -1,5 +1,5 @@
 // Copyright (c) 2015-2016 The btcsuite developers
-// Copyright (c) 2016-2019 The Decred developers
+// Copyright (c) 2016-2020 The Decred developers
 // Use of this source code is governed by an ISC
 // license that can be found in the LICENSE file.
 
@@ -17,6 +17,7 @@ import (
 	"bytes"
 	"compress/bzip2"
 	"encoding/gob"
+	"errors"
 	"fmt"
 	"os"
 	"path/filepath"
@@ -91,8 +92,8 @@ func loadBlocks(t *testing.T, dataFile string, network wire.CurrencyNet) ([]*dcr
 // checkDbError ensures the passed error is a database.Error with an error code
 // that matches the passed error code.
 func checkDbError(t *testing.T, testName string, gotErr error, wantErrCode database.ErrorCode) bool {
-	dbErr, ok := gotErr.(database.Error)
-	if !ok {
+	var dbErr database.Error
+	if !errors.As(gotErr, &dbErr) {
 		t.Errorf("%s: unexpected error type - got %T, want %T",
 			testName, gotErr, database.Error{})
 		return false
@@ -407,7 +408,7 @@ func testBucketInterface(tc *testContext, bucket database.Bucket) bool {
 		err := bucket.ForEach(func(k, v []byte) error {
 			return forEachError
 		})
-		if err != forEachError {
+		if !errors.Is(err, forEachError) {
 			tc.t.Errorf("ForEach: inner function error not "+
 				"returned - got %v, want %v", err, forEachError)
 			return false
@@ -470,7 +471,7 @@ func testBucketInterface(tc *testContext, bucket database.Bucket) bool {
 		err = bucket.ForEachBucket(func(k []byte) error {
 			return forEachError
 		})
-		if err != forEachError {
+		if !errors.Is(err, forEachError) {
 			tc.t.Errorf("ForEachBucket: inner function error not "+
 				"returned - got %v, want %v", err, forEachError)
 			return false
@@ -928,7 +929,7 @@ func testMetadataTxInterface(tc *testContext) bool {
 		return nil
 	})
 	if err != nil {
-		if err != errSubTestFail {
+		if !errors.Is(err, errSubTestFail) {
 			tc.t.Errorf("%v", err)
 		}
 		return false
@@ -940,7 +941,7 @@ func testMetadataTxInterface(tc *testContext) bool {
 	err = tc.db.View(func(tx database.Tx) error {
 		return viewError
 	})
-	if err != viewError {
+	if !errors.Is(err, viewError) {
 		tc.t.Errorf("View: inner function error not returned - got "+
 			"%v, want %v", err, viewError)
 		return false
@@ -973,8 +974,8 @@ func testMetadataTxInterface(tc *testContext) bool {
 		// Return an error to force a rollback.
 		return forceRollbackError
 	})
-	if err != forceRollbackError {
-		if err == errSubTestFail {
+	if !errors.Is(err, forceRollbackError) {
+		if errors.Is(err, errSubTestFail) {
 			return false
 		}
 
@@ -998,7 +999,7 @@ func testMetadataTxInterface(tc *testContext) bool {
 		return nil
 	})
 	if err != nil {
-		if err != errSubTestFail {
+		if !errors.Is(err, errSubTestFail) {
 			tc.t.Errorf("%v", err)
 		}
 		return false
@@ -1023,7 +1024,7 @@ func testMetadataTxInterface(tc *testContext) bool {
 		return nil
 	})
 	if err != nil {
-		if err != errSubTestFail {
+		if !errors.Is(err, errSubTestFail) {
 			tc.t.Errorf("%v", err)
 		}
 		return false
@@ -1048,7 +1049,7 @@ func testMetadataTxInterface(tc *testContext) bool {
 		return nil
 	})
 	if err != nil {
-		if err != errSubTestFail {
+		if !errors.Is(err, errSubTestFail) {
 			tc.t.Errorf("%v", err)
 		}
 		return false
@@ -1073,7 +1074,7 @@ func testMetadataTxInterface(tc *testContext) bool {
 		return nil
 	})
 	if err != nil {
-		if err != errSubTestFail {
+		if !errors.Is(err, errSubTestFail) {
 			tc.t.Errorf("%v", err)
 		}
 		return false
@@ -1498,7 +1499,7 @@ func testBlockIOTxInterface(tc *testContext) bool {
 		return nil
 	})
 	if err != nil {
-		if err != errSubTestFail {
+		if !errors.Is(err, errSubTestFail) {
 			tc.t.Errorf("%v", err)
 		}
 		return false
@@ -1540,8 +1541,8 @@ func testBlockIOTxInterface(tc *testContext) bool {
 
 		return forceRollbackError
 	})
-	if err != forceRollbackError {
-		if err == errSubTestFail {
+	if !errors.Is(err, forceRollbackError) {
+		if errors.Is(err, errSubTestFail) {
 			return false
 		}
 
@@ -1558,7 +1559,7 @@ func testBlockIOTxInterface(tc *testContext) bool {
 		return nil
 	})
 	if err != nil {
-		if err != errSubTestFail {
+		if !errors.Is(err, errSubTestFail) {
 			tc.t.Errorf("%v", err)
 		}
 		return false
@@ -1599,7 +1600,7 @@ func testBlockIOTxInterface(tc *testContext) bool {
 		return nil
 	})
 	if err != nil {
-		if err != errSubTestFail {
+		if !errors.Is(err, errSubTestFail) {
 			tc.t.Errorf("%v", err)
 		}
 		return false
@@ -1616,7 +1617,7 @@ func testBlockIOTxInterface(tc *testContext) bool {
 		return nil
 	})
 	if err != nil {
-		if err != errSubTestFail {
+		if !errors.Is(err, errSubTestFail) {
 			tc.t.Errorf("%v", err)
 		}
 		return false
@@ -1647,7 +1648,7 @@ func testBlockIOTxInterface(tc *testContext) bool {
 		return nil
 	})
 	if err != nil {
-		if err != errSubTestFail {
+		if !errors.Is(err, errSubTestFail) {
 			tc.t.Errorf("%v", err)
 		}
 		return false